Thienopyrimidine-2,4-dione derivatives and intermediates thereof

ABSTRACT

The synthesis of thienopyrimidine-2,4-dione derivatives and their urea intermediates is described. The novel urea intermediates and thienopyrimidine-2,4-dione derivatives are generally vasodilating agents and anti-hypertensive agents. The compounds are useful as cardiovascular agents.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel thienopyrimidine-2,4-dione derivatives of general formula I: ##STR1## or their intermediates of general formula II: ##STR2## as described further below. The derivatives and intermediates are useful as cardiovascular agents, such as antihypertensive or general vasodilatng agents.

2. Description of the Prior Art

Several thienopyrimidine compounds have been previously described which have a variety of biological activities. For example, Chem. Abstr. 87, 201452 describes thienopyrimidine-2,4-dione compounds of the formula ##STR3## in which R₂ is methyl or phenyl and R₃ is acetylenic chains with amine termini. No utility was disclosed for these compounds.

Belgian Pat. No. 799238A describes thienopyrimidine-2-one compounds as CNS, uricosuric, antiviral or antiinflammatory agents. The compounds have the general formula ##STR4## Belgain Pat. No. 796003 describes similar compounds having an additional substituent on the thiophene ring. The latter compounds have the same activity as the former compounds.

British Pat. No. 1,057612 describes several thienopyrimidine compounds having different activities such as fungistatic, bacteriostatic, cytostatic, antiphlogistic, CNS stimulating and cardiovascular activity. Compounds of the formula ##STR5## where R₁ or R₂ are N-methylpiperazine are said to have good cardiovascular effects. Additional compounds include those of the following general formulas: ##STR6##

Derwent Accession No. 66-23,767/00 describes compounds of the formula ##STR7## which have coronary or peripheral vasodilator activity as well as CNS activity. In the dione compounds, R₅ and R₆ may be alkyl or aryl.

Chem.Abs. 104, 19606q (EP 150469) describes thienopyrimidine compounds which are antidepressants and which have the formula: ##STR8## where R may be aryl or thieno and R₁ and R₂ may be hydrogen, alkyl, halo or alkylene.

Finally, H. K. Gaklar et al., Indian J. Chem. Sec. B, 24B, 432 (1985) describes the preparation of thienopyrimidine-4-ones having the formula: ##STR9## No biological activity was disclosed for these compounds.

None of the thienopyrimidine compounds of the prior art discussed above contain an N-alkyl-N-arylpiperazine moiety, i.e., ##STR10## at the 3-position. Furthermore, several of the compounds are not diones and do not contain the same substituents at the 1-position of the present invention.

SUMMARY OF THE INVENTION

The present invention is directed to thienopyrimidine compounds of the formula ##STR11## where ##STR12## may be ##STR13## R₁ and R₂ may be the same or different and may be hydrogen, F, Cl, Br, nitro, C₁ -C₃ alkyl or R₁ and R₂ together may be --(CH₂)₄ -- when ##STR14## R₃ may be hydrogen, C₁ -C₁₀ alkyl, C₃ -C₈ branched-chain alkyl, C₃ -C₆ alkenyl, C₃ -C₆ alkynyl, --(CH₂)_(m) --CO₂ R₅, --(CH₂)_(m) CONR₆ R₇, --COR₈ or --CO₂ R₉ ;

R₅ may be hydrogen, C₁ -C₃ alkyl, pharmaceutically acceptable alkali metal ion, pharmaceutically acceptable alkaline earth metal ion or pharmaceutically acceptable quaternary ammonium ion;

R₆ and R₇ may be the same or different and may be hydrogen or C₁ -C₃ alkyl;

R₈ may be C₁ -C₅ alkyl, C₃ -C₅ branched-chain alkyl, --(CH₂)_(m) --CO₂ R₅, phenyl or phenyl substituted by F, Cl, Br, C₁ -C₂ alkyl or C₁ -C₂ alkoxy;

R₉ may be C₁ -C₃ alkyl;

Ar may be ##STR15## R₁₀ and R₁₁ may be the same or different and may be hydrogen, NO₂, CF₃, F, Cl, Br, C₁ -C₃ alkyl or C₁ -C₂ alkoxy;

m may be 2-6; and

n may be 2-4.

The present invention is further directed to intermediates of the compounds of formula I having the formula ##STR16## where ##STR17## R₁, R₂, Ar and n are as defined above and R₄ may be C₁ -C₂ alkyl.

The compounds of formula I or II are useful as cardiovascular agents, such as antihypertensive agents or general vasodilating agents, especially renal vasodilating agents.

DETAILED DESCRIPTION OF THE INVENTION

The invention in its broadest aspects relates to thienopyrimidine-2,4-dione compounds and intermediates thereof which have cardiovascular activity, such as antihypertensive activity or general vasodilator activity, in mammals. The thienopyrimidine-2,4-dione compounds of the invention demonstrating a cardiovascular activity are shown by formula I above. The intermediates of these compounds which also have a cardiovascular activity are shown by formula II above. The thienopyrimidine-2,4-dione compounds and intermediates which have a cardiovascular activity all contain a nitrogen, either in the pyrimidine ring of the thienopyrimidine-2,4-diones or in the urea moiety of the intermediates, which is substituted by the group ##STR18## where n and Ar are as defined above.

The thienopyrimidine component of formula I may be either thieno[3,4-d]pyrimidine, thieno[2,3-d]pyrimidine or thieno[3,2-d]pyrimidine. The S atom in the intermediate compounds of formula II may occupy the equivalent position in the thiophene ring as it does in the thienopyrimidine compounds.

The preferred compounds of the present invention are those wherein R₁ is hydrogen or alkyl; R₂ is hydrogen or alkyl; R₃ is hydrogen, alkyl, branched-chain alkyl, alkenyl, alkynyl, --(CH₂)_(m) --CO₂ R₅ ; --COR₈ or --CO₂ R₉ ; R₅ is hydrogen or alkyl; R₈ is alkyl, branched-chain alkyl, --(CH₂)_(m) --CO₂ R₅, phenyl or chlorophenyl; Ar is phenyl, chlorophenyl, fluorophenyl, methylphenyl or alkoxyphenyl; m is 2-4, and n is 2-3.

The compounds of formulas I and II can be prepared as shown in the following scheme. ##STR19##

The compounds of formula II are prepared as follows:

An aminothiophene ester 1 is mixed with a chloroalkyl isocyanate 2 in an inert solvent at about 75° C. to about 115° C. about 1 to about 24 hours and the chloroalkyl urea 3 is produced as a white solid. The aminothiophene esters 1 are obtained commercially or prepared by the procedure of B. R. Baker, et al., J. Org. Chem. 18, 138 (1953). Suitable chloroalkyl isocyanates 2 include the 2-chloroethyl, 3-chloropropyl and 4-chlorobutyl isocyanates. The former two isocyanates are obtained commercially and the latter isocyanate is prepared according to S. Handa, et al., Ger. Offen. 2,622,194 (Chem. Abst. 86, 89372u (1977)). Inert solvents which may be utilized include toluene, tetrahydrofuran, dioxane and chloroform.

The crystalline chloroalkyl urea 3 is then reacted with an N-arylpiperazine, where the aryl group (Ar) is as defined above, in an inert solvent at about 60° C. to about 80° C. for about 1 to about 4 days in the presence of an alkali metal base and a catalyst to produce the alkylpiperazine urea 4. Suitable inert solvents for this step include tetrahydrofuran, dioxane, dimethylformamide, acetonitrile and isopropanol. A preferred base is sodium or potassium bicarbonate and the preferred catalyst is sodium or potassium iodide. The alkylpiperazine urea 4 is isolated as a solid.

The compounds of formula I are prepared as follows:

An alkylpiperazine urea 4 is prepared as described above. The urea 4 can be isolated and converted to a thienopyrimidine-2,4-dione 5 or it can be converted directly. The conversion is accomplished in an alcoholic solvent which contains an alkali metal base at about 25° C. to about 65° C. for about 1/2 hour to about 24 hours. Suitale alcohols include methanol, ethanol and isopropanol. Preferred alkali metal bases include sodium or potassium hydroxide or sodium hydride. The resulting novel thienopyrimidine-2,4-dione 5 is obtained as a solid.

The dione 5 can be alkylated at the 1-position by treatment in an inert solvent with an alkali metal base and subsequent treatment with an alkyl halide, R₃ X, at about 5° C. to about 25° C. for about 11/2 to about 16 hours to produce the alkylated derivative 7 as a white crystalline solid. Suitable inert solvents include tetrahydrofuran, dimethoxyethane and dimethylformamide. The preferred alkali metal base is sodium hydride. Alkyl halides which can be used are commericially available and include those wherein the alkyl group is methyl, ethyl, isopropyl, decyl, 3-(methoxycarbonyl)propyl, 6-(ethoxycarbonyl)hexyl, allyl and propargyl, among others. The halide may be bromide or iodide.

The carboxylic acid derivative of 7, i.e., R₃ is --(CH₂)_(m) CO₂ H, can be prepared by dissolving the carboxylic ester derivative of 7, i.e., R₃ is --(CH₂)_(m) CO₂ R₅ where R₅ is a lower alkyl (prepared as in the preceding paragraph), in an aqueous alcoholic solvent and treating with an alkali metal base at about 25° C. for about 3 to about 24 hours. The carboxylic acid derivative is a white solid after neutralization. Suitable alcohols include methanol and ethanol. Preferred bases are sodium hydroxide and potassium hydroxide.

The carboxylic acids may be converted to their corresponding pharmaceutically acceptable salts by dissolving the acids in an alcoholic solvent, for example methanol or ethanol, and treating them with an appropriate base. Appropriate bases include sodium hydroxide, potassium hydroxide, calcium hydroxide, triethylamine, tetrabutylammonium hydroxide and the like. The salts are obtained as solids after removal of the solvent.

The carboxylic ester derivative of 7, i.e., R₃ is --(CH₂)_(m) CO₂ R₅, can be converted to the corresponding amides, i.e., R₃ is --(CH₂)_(m) CONR₆ R₇, by standard condensation procedures or by the method of S. Weinreb, et al., Tetrahedron Letters, 4174 (1977). In the latter method, the ester is added to an inert solvent, such as methylene chloride, containing trimethylaluminum and an amine at about 25° C. to about 41° C. for about 5 to about 45 hours. Suitable amines include ammonia, methylamine, dimethylamine or propylamine and the like. The amides are isolated as solids.

The dione 5 can be acylated at the 1-position by refluxing the dione 5 with an acylating agent, such as acetic anhydride or benzoic anhydride, for about 1 to about 24 hours. Alternatively, the acylated derivative 7 can be prepared by treating the dione 5 with a strong base and an acid chloride in a polar solvent. The preferred strong bases are sodium hydride or lithium diisopropylamide. Suitable polar solvents include tetrahydrofuran, dimethyl sulfoxide, dimethylformamide and N-methylpyrrolidone. Acid chlorides include acetyl chloride, trimethylacetyl chloride, benzoyl chloride and the like. A final approach is to treat the dione 5 with an amine base such as triethylamine and an acid chloride in a solvent such as methylene chloride or chloroform.

The dione 5 can be halogenated by dissolving it in an inert solvent, such as methylene chloride or chloroform, and treating it with a halogenating agent to produce the halogen derivative 6. Suitable halogenating agents include sulfuryl chloride, N-chlorosuccinimide, N-bromosuccinimide, bromine and the like. Alternatively, the halogen derivatives 6 can be prepared by treating the urea 3 in the same manner and then reacting the halogenated urea 3 with the N-arylpiperazine.

The nitro derivative 7 can be prepared in a similar fashion by treating either the dione 5 or urea 3 with nitric acid in acetic anhydride or similar nitrating conditions. The nitrated urea 3 is then reacted with the N-arylpiperazine and reacted as above to give 5.

Pharmaceutical compositions containing a compound of the present invention as the active ingredient in intimate admixture with a pharmaceutical carrier can be prepared according to conventional pharmaceutical compounding techniques. The carrier may take a wide variety of forms depending on the form of preparation desired for administration, e.g., intravenous, oral or parenteral. In preparing the compositions in oral dosage form, any of the usual pharmaceutical media may be employed, such as, for example, water, glycols, oils, alcohols, flavoring agents, preservatives, coloring agents and the like in the case of oral liquid preparations (such as, for example, suspensions, elixirs and solutions); or carriers such as starches, sugars, diluents, granulating agents, lubricants, binders, disintegrating agents and the like in the case of oral solid preparations (such as, for example, powders, capsules and tablets). Because of their ease in administration, tablets and capsules represent the most advantageous oral dosage unit form, in which case solid pharmaceutical carriers are obviously employed. If desired, tablets may be sugar-coated or enteric-coated by standard techniques. For parenterals, the carrier will usually comprise sterile water, though other ingredients, for example, to aid solubility or for preservative purposes, may be included. Injectable suspensions may also be prepared, in which case appropriate liquid carriers, suspending agents and the like may be employed. The pharmaceutical compositions will generally contain dosage unit, e.g., tablet, capsule, powder, injection, teaspoonful and the like, from about 0.5 to about 100 mg/kg, and preferably from about 1 to about 5 mg/kg of the active ingredient.

The following examples describe the invention in greater particularity and are intended to be a way of illustrating but not limiting the invention.

EXAMPLE 1 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

(a) An aqueous solution of 9.65 g (50 mmol) of methyl 4-amino-3-thiophenecarboxylate hydrochloride (B. R. Baker, et al., J. Org. Chem., 18, 138 (1953)) was treated with a saturated NaHCO₃ solution and then extracted with CH₂ Cl₂. After drying the CH₂ Cl₂ extracts over MgSO₄, the organic solution was evaporated to give the amine free base. This material was dissolved in 100 ml of toluene and treated with 4.7 ml (55 mmol) of 2-chloroethyl isocyanate. After this solution had been warmed to 100° C. for 3 hours, it was cooled and 7.9 g of N-(3-carbomethoxythien-4-yl)-N'-(2-chloroethyl)urea precipitated and was collected by filtration. The mother liquor afforded an additional 4.3 g (12.2 g total, 93%) of product which was recrystallized from CH₂ Cl₂ /ether/hexane (2/2/1), mp 110°-112° C.

Theor. C₉ H₁₁ ClN₂ O₃ S: C, 41.14; H, 4.22; N, 10.66. Found: C, 41.04; H, 4.17; N, 10.97.

The product produced in the preceding paragraph (5.2 g, 20 mmol) was dissolved in 60 ml of dry dimethylformamide and treated with 5.89 g (30 mmol) of 1-(2-methoxyphenyl)piperazine. After this solution had been warmed to 80° C. under nitrogen for 16 hours, it was cooled and 2.3 g of 1-(2-methoxyphenyl)piperzine hydrochloride was removed by filtration. The filtrate was concentrated in vacuo and the residue was purified by flash slica gel chromatography using 1-3% EtOH in CH₂ Cl₂. The title compound was isolated and converted with isopropanolic hydrogen chloride to its hydrochloride salt (0.78 g , 9.2%), mp 270°-273° C. (dec).

Theor. C₁₉ H₂₂ N₄ O₃ S.HCl: C, 53.95; H, 5.48; N, 13.25. Found: C, 54.10; H, 5.59; N, 12.82.

(b) A 500 ml tetrahydrofuran mixture containing 13.1 g (50 mmol) of N-(3-carbomethoxythien-4-yl)-N'-(2-chloroethyl)urea from (a), 35 g (150 mmol) of 1-(2-methoxyphenyl)piperazine hydrochloride, 21 g (250 mmol) of sodium bicarbonate and 3.75 g (25 mmol) of sodium iodide was heated to reflux under nitrogen for 4 days. The tetrahydrofuran was removed in vacuo and the residue was partitioned between H₂ O and CH₂ Cl₂. The CH₂ Cl₂ extracts were dried over MgSO₄ and evaporated to dryness. This residue which contained the title compound of Example 2 was dissolved in 300 ml of methanol and treated with 4.5 g (56 mmol) of 50% NaOH. After the solution had been stirred at room temperature for 16 hours, the resulting precipitate was collected by filtration to afford 9.7 g of the title compound. The filtrate was purified by flash silica gel chromatography using 1-5% MeOH in CH₂ Cl₂. There was obtained an additional 3.4 g of the title compound (13.1 g total, 68%) which was converted to its hydrochloride salt with isopropanolic hydrogen chloride, 9.1 g, mp 273°-275° C. (dec).

EXAMPLE 2 N-(3-Carbomethoxythien-4-yl)-N'-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]urea

(a) The title compound was also produced by the procedure of Example 1(a). The silica gel chromatography described in the second paragraph afforded the title compound as a faster running component which was converted with isopropanolic hydrogen chloride to its dihydrochloride salt (1.1 g, 11%), mp 195°-199° C.

Theor. C₂₀ H₂₆ N₄ O₄ S.2HCl: C, 48.88; H, 5.74; N, 11.40. Found: C, 48.85; H, 5.73, N, 11.59.

(b) Prepared as described in Example 1(b).

EXAMPLE 3 3-[2-[4-(2-Methylphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-(2-methylphenyl)piperazine hydrochloride (40 mmol). The title compound was isolated in 38% yield (2.85 g) after recrystallization from EtOAc/CH₂ Cl₂, mp 214°-216° C.

Theor. C₁₉ H₂₂ N₄ O₂ S: C, 61.60; H, 5.99; N, 15.12. Found: C, 61.22; H, 6.10; N, 15.23.

EXAMPLE 4 3-[2-[4-(2-Chlorophenyl)piperazin-1yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-(2-chlorophenyl)piperazine (40 mmol). The title compound was isolated in 39% yield (3.03 g) after recrystallization from EtOH/EtOAc (1/3), mp 205°-207° C. (dec).

Theor. C₁₈ H₁₉ ClN₄ O₂ S: C, 55.30; H, 4.90; N, 14.33. Found: C, 54.87; H, 5.03; N, 14.20.

EXAMPLE 5 3-[2-[4-(3-Chlorophenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-(3-chlorophenyl)piperazine hydrochloride (40 mmol). The title compound was isolated in 19% yield (1.5 g) after crystallization from MeOH/EtOAc, mp 207°-208° C.

Theor. C₁₈ H₁₉ ClN₄ O₂ S: C, 55.30; H, 4.90; N, 14.33. Found: C, 55,50; H, 4.98; N, 14.10.

EXAMPLE 6 3-[2-[4-(4-Methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-(4-methoxyphenyl)piperazine hydrochloride (40 mmol). The title compound was isolated in 14.6% yield (1.13 g) after recrystallization from MeOH/ether, mp 238°-239° C.

Theor. C₁₉ H₂₂ N₄ O₃ S: C, 59.05; H, 5.74; N, 14.50. Found: C, 59.12; H, 5.81; N, 14.70.

EXAMPLE 7 3-[2-[4-(3-Methoxyphenyl)piperazin-1-yl)ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-(3-methoxyphenyl)piperazine dihydrochloride (40 mmol). The title compound was isolated in 18% yield (1.4 g) after recrystallization from EtOH/hexane, mp 184.5°-185.5° C.

Theor. C₁₉ H₂₂ N₄ O₃ S: C, 59.05; H, 5.74; N, 14.50. Found: C, 58.86; H, 5.85; N, 14.47.

EXAMPLE 8 3-[2-[4-(4-Chlorophenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-(4-chlorophenyl)piperazine dihydrochloride (40 mmol). The title compound was converted to its hydrochloride salt with isopropanolic hydrogen chloride and isolated in 26% yield (2.21 g), mp>250° C.

Theor. C₁₈ H₁₉ ClN₄ O₂ S.HCl: C, 50.59; H, 4.72; N, 13.11. Found: C, 50.51; H, 4.80; N, 12.82.

EXAMPLE 9 3-[2-[4-(4-Fluorophenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-(4-fluorophenyl)piperazine (40 mmol). The title compound was converted to its hydrochloride salt with isopropanolic hydrogen chloride and isolated in 18% yield (1.46 g), mp>250° C.

Theor. C₁₈ H₁₉ FN₄ O₂ S.HCl: C, 52.62; H, 4.66; N, 13.64. Found: C, 52.35; H, 4.86; N, 13.85.

EXAMPLE 10 3-[2-(4-Phenylpiperazin-1-yl)ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using 1-phenylpiperazine (40 mmol). The title compound was converted to its hydrochloride salt with isopropanolic hydrogen chloride and isolated in 21% yield (1.62 g), mp>250° C.

Theor. C₁₈ H₂₀ N₄ O₂ S.HCl: C, 55.03; H, 5.13; N, 14.26. Found: C, 55.31; H, 5.53; N, 14.29.

EXAMPLE 11 3-[3-[4-(2-Methoxyphenyl)piperazin-1-yl]propyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using N-(3-carbomethoxythien-4-yl)-N'-(3-chloropropyl)urea as the intermediate urea (5.52 g, 20 mmol) which was produced according to the procedure in Example 1 (a) with the exception that the isocyanate used was 3-chloropropyl isocyanate (55 mmol). This new urea was afforded in 61% yield (8.5 g) and crystallized from ether/hexane, mp 80°-83° C.

Theor. C₁₀ H₁₃ ClN₂ O₃ S: C, 43.40; H, 4.74; N, 10.12. Found: C, 43.31; H, 4.80; N, 10.28.

The title compound was isolated in 56% yield (4.5 g) and was crystallized from EtOH, mp 187°-188.5° C.

Theor. C₂₀ H₂₄ N₄ O₃ S: C, 59.98; H, 6.04; N, 13.99. Found: C, 59.69; H, 6.04; N, 13.95.

EXAMPLE 12 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-5-methylthieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 1(b) using N-(3-carbomethoxy-4-methylthien-4-yl)-N'-(2-chloroethyl)urea as the intermediate urea (5.52 g, 20 mmol) which was produced according to the procedure in Example 1(a) with the exception that the thiophene used was methyl 4-amino-2-methyl-3-thiophenecarboxylate hydrochloride (10.4 g, 50 mmol) which was prepared by the method of D. Binder et al. (Arch. Pharm. (Weinheim, Ger.), 314(6), 557 (1981)). The title compound was converted to its hydrochloride salt with isopropanolic hydrogen chloride and isolated in 46% yield (4.0 g), mp 265°-267° C. (dec).

Theor. C₂₀ H₂₄ N₄ O₃ S.HCl: C, 54.97; H, 5.77; N, 12.82. Found: C, 54.58; H, 5.88; N, 12.85.

When in the above procedure, methyl 4-amino-5-methyl-3-thiophenecarboxylate hydrochloride, methyl 4-amino-2,5-diethyl-3-thiophenecarboxylate hydrochloride, methyl 4-amino-2-nitro-3-thiophenecarboxylate hydrochloride or methyl 4-amino-2-propyl-3-thiophenecarboxylate hydrochloride is employed, the corresponding 7-methyl, 5,7-diethyl, 5-nitro or 5-propyl derivative is obtained.

EXAMPLE 13 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-methylthieno[3,4-d]pyrimidine-2,4-dione

To a 50 ml tetrahydrofuran solution of 1.5 g (3.88 mmol) of the product of Example 1(a) (as its free base) under nitrogen was added 0.2 g (5.82 mmol) of 60% NaH. After stirring at room temperature for 30 minutes, the orange solution was treated with 0.24 ml (3.88 mmol) of methyl iodide. The reaction was quenched with H₂ O after 16 hours and the tetrahydrofuran was removed by evaporation at reduced pressure. The tan residue was crystallized from CH₂ Cl₂ /ether (1:1) to afford the title compound in 41% yield (0.64 g), mp 167°-167.5° C.

Theor. C₂₀ H₂₄ N₄ O₃ S.1/4H₂ O: C, 59.31; H, 6.10; N, 13.84. Found: C, 59.48; H, 6.25; N, 13.64.

When in the above procedure, pentyl iodide, decyl iodide or 1-bromo-2-methylpropane is employed as the alkylating agent, the corresponding 1-pentyl, 1-decyl or 1-(2-methyl-propyl) derivative is obtained.

EXAMPLE 14 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-(propen-3-yl)thienol[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent and allyl bromide (4.4 mmol) as the alkylating agent. The crude product was purified by flash silica gel chromatography using EtOAc/hexane (40/60). The title compound was isolated in 56% yield (0.96 g) after recrystallization from CH₂ Cl₂ /hexane, mp 131°-132° C.

Theor. C₂₂ H₂₆ N₄ O₃ S: C, 61.95; H, 6.14; N, 13.14. Found: C, 61.83; H, 6.24; N, 13.04.

When in the above procedure, 4-bromo-1-butene or 6-bromo-1-hexene is employed as the alkylating agent, the corresponding 1-(buten-4-yl) or 1-(hexen-6-yl) derivative is obtained.

EXAMPLE 15 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-(propyn-3-yl)thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent and propargyl bromide (4.4 mmol) as the alkylating agent. The crude product was purified by flash silica gel chromatography using EtOAc/hexane (1:1). The title compound was isolated in 49% yield (0.84 g) after recrystallization from ether/hexane, mp 142°-143° C.

Theor. C₂₂ H₂₄ N₄ O₃ S: C, 62.24; H, 5.70; N, 13.20. Found: C, 61.99; H, 5.83; N, 13.28.

EXAMPLE 16 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-(octyl)thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent and octyl bromide (12 mmol) as the alkylating agent. The crude product was purified by flash silica gel chromatography using EtOAc/hexane (1:1). The title compound was isolated in 47% yield (0.94 g) after recrystallization from ether/hexane, mp 82°-84° C.

Theor. C₂₇ H₃₈ N₄ O₃ S: C, 65.03; H, 7.68; N, 11.24. Found: C, 65.26; H, 7.73; N, 11.35.

EXAMPLE 17 1-(2-Methoxycarbonyl)ethyl-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent and methyl 3-bromopropionate (4.4 mmol) as the alkylating agent. The crude product was purified by flash silica gel chromatography using 50-70% EtOAc in hexane. The title compound was isolated in 47% (0.89 g) yield after recrystallization from ether, mp 140°-140.5° C.

Theor. C₂₃ H₂₈ N₄ O₅ S: C, 58.45; H, 5.97; N, 11.86. Found: C, 58.21; H, 6.08; N, 11.89.

When the above product is treated with ammonia in accordance with Weinreb et al., vide supra, the corresponding 1-(3-propanamide)derivative is obtained.

EXAMPLE 18 1-[3-(Ethoxycarbonyl)propyl]-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent and ethyl 4-bromobutyrate (3.9 mmol) as the alkylating agent. The title compound was produced in 65% yield (0.85 g) after recrystallization from ether, mp 108°-109.5° C.

Theor. C₂₅ H₃₂ N₄ O₅ S: C, 59.98; H, 6.44; N, 11.19. Found: C, 60.08; H, 6.47; N, 11.27.

EXAMPLE 19 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced from N-(2-carbomethoxythien-3-yl)-N'-(2-chloroethyl)urea which was prepared in the same manner as described for N-(3-carbomethoxythien-4-yl)-N'-(2-chloroethyl)urea in Example 1(a) with the exception that the thiophene was methyl 3-amino-2-thiophenecarboxylate (28.3 g, 0.18 mol). This new urea was obtained in 56% yield (26.6 g) isolated from the reaction as a crystalline solid, mp 139°-142° C.

Theor. C₉ H₁₁ ClN₂ O₃ S: C, 41.15; H, 4.22; N, 10.66. Found: C, 41.30; H, 4.22; N, 10.68.

The product produced in the preceding paragraph (8.44 g, 32.1 mmol) was dissolved in 200 ml of tetrahydrofuran and treated with 14.68 g (64.2 mmol) of 1-(2-methoxyphenyl)piperazine hydrochloride, 8.12 g (96.6 mmol) of sodium bicarbonate and 1.7 g of sodium iodide. After the mixture had been refluxed for 2.5 days, the tetrahydrofuran was removed in vacuo and the residue was partitioned between H₂ O and CH₂ Cl₂. The combined CH₂ Cl₂ extracts were dried over MgSO₄ and concentrated in vacuo to afford a residue that was purified by flash silica gel chromatography using 2% MeOH in CH₂ Cl₂. The urea, N-(2-carbomethoxythien-3-yl)-N'-[2-[4-[2-methoxyphenyl)piperazin-1-yl)ethyl]urea, was obtained in 67% yield (9.0 g), mp 149°-151° C.

Theor. C₂₀ H₂₆ N₄ O₄ S: C, 57.39; H, 6.26; N, 13.39. Found: C, 57.05; H, 6.27; N, 13.51.

A solution of this intermediate (7.0 g, 16.7 mmol) in 50 ml 1N methanolic KOH was refluxed for 1 hour, poured into 200 ml of ice water and neutralized. The title compound was isolated in 72% yield (4.65 g) after trituration with hot ethanol, mp 222°-223° C.

Theor. C₁₉ H₂₂ N₄ O₃ S.1/4H₂ O: C, 58.37; H, 5.80; N, 14.33. Found: C, 58.56; H, 5.79; N, 14.26.

EXAMPLE 20 3-[2-[4-(2-Methylphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using 1-(2-methylphenyl)piperazine hydrochloride (22.8 mmol) and an initial reflux period of 4 days. The intermediate urea, N-(2-carbomethoxythien-3-yl)-N'-[2-[4-(2-methylphenyl)piperazin-1-yl]ethyl]urea, was isolated in 48% yield (2.2 g), mp 118°-123° C.

The product from the preceding paragraph (2.1 g, 5.2 mmol) was converted to the title compound as described in Example 19 in 73% yield (1.4 g) after it had been triturated in boiling ethanol, mp 212°-214° C.

Theor. C₁₉ H₂₂ N₄ O₂ S: C, 61.60; H, 5.99; N, 15.12. Found: C, 61.74; H, 6.26; N, 14.99.

EXAMPLE 21 3-[2-[4-(2-Chlorophenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using 1-(2-chlorophenyl)piperazine hydrochloride (22.8 mmol) and an initial reflux period of 4 days. The intermediate urea, N-(2-carbomethoxythien-3-yl)-N'-[2-[4-(2-chlorophenyl)piperazin-1-yl]ethyl]urea, was isolated in 59% yield (2.88 g), mp 61°-65° C.

The product from the preceding paragraph (2.8 g, 6.62 mmol) was converted to the title compound in 77% yield (1.99 g), mp 193°-196° C., using the procedure in Example 19.

Theor. C₁₈ H₁₉ ClN₄ O₂ S: C, 55.31; H, 4.90; N, 14.35. Found: C, 54.95; H, 4,93; N, 14.12.

EXAMPLE 22 3-[2-[4-(4-Methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using 1-(4-methoxyphenyl)piperazine hydrochloride (22.8 mmol). The intermediate urea, N-(2-carbomethoxythien-3-yl)-N'-[2-[4-(4-methoxyphenyl)piperazin-1-yl]ethyl]urea, was isolated in 34% yield (1.6 g), mp 158°-160° C.

Theor. C₂₀ H₂₆ N₄ O₄ S: C, 57.29; H, 6.26; N, 13.39. Found: C, 57.29; H, 6.35; N, 13.30.

The product from the preceding paragraph (1.6 g, 3.86 mmol) was converted to the title compound in 80% yield (1.2 g), mp 130°-131° C., using the procedure in Example 19.

Theor. C₁₉ H₂₂ N₄ O₃ S: C, 59.05; H, 5.74; N, 14.50. Found: C, 58.87; H, 5.85; N, 14.37.

When in the above procedure, methyl 3-amino-5-methyl-2-thiophenecarboxylate hydrochloride, methyl 3-amino-4-methyl-2-thiophenecarboxylate hydrochloride, methyl 3-amino-4,5-diethyl-2-thiophenecarboxylate hydrochloride, methyl 3-amino-5-nitro-2-thiophenecarboxylate hydrochloride or methyl 3-amino-5-propyl-2-thiophenecarboxylate hydrochloride is employed, the corresponding 5-methyl, 7-methyl, 5,7-diethyl, 5-nitro or 5-propyl derivative is obtained.

EXAMPLE 23 3-[2-(4-Phenylpiperazin-1-yl)ethyl]thieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using 1-phenylpiperazine (28.5 mmol) and an initial reflux period of 4 days. The intermediate urea, N-(2-carbomethoxythien-3-yl)-N'-[2-(4-phenylpiperazin-1-yl)ethyl]urea, was isolated in 57% yield (2.1 g), mp 162°-164° C.

Theor. C₁₉ H₂₄ N₄ O₃ S: C, 58.74; H, 6.23; N, 14.42. Found: C, 58.31; H, 6.03; N, 14.21.

The product from the preceding paragraph (2.1 g, 5.4 mmol) was converted to the title compound in 62% yield (1.2 g), mp 215°-217° C., using the procedure in Example 19.

Theor. C₁₈ H₂₀ N₄ O₂ S: C, 60.65; H, 5.66; N, 15.72. Found: C, 60.84; H, 5.65; N, 15.66.

EXAMPLE 24 3-[3-[4-(2-Methoxyphenyl)piperazin-1-yl]propyl]thienol[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 with the exception that the initial urea, N-(2-carbomethoxythien-3-yl)-N'-(3-chloropropyl)urea, was produced according to the procedure in Example 19 except that the isocyanate used was 3-chloropropyl isocyanate (76 mmol) and the reflux period was 2.5 days. This chloropropyl urea was crystallized from hexanes in 61% yield (10.6 g), mp 78°-84° C.

Theor. C₁₀ H₁₃ ClN₂ O₃ S: C, 43.40; H, 4.73; N, 10.12. Found: C, 43.21; H, 4.62; N, 10.02.

The product from the preceding paragraph (5.0 g, 19.2 mmol) was converted to the intermediate urea, N-(2-carbomethoxythien-3-yl)-N'-[3-[4-(2-methoxyphenyl)piperazin-1-yl]propyl]urea, using the procedure in Example 19 in 79% yield (6.4 g), mp 149°-151° C.

Theor. C₂₁ H₂₈ N₄ O₄ S: C, 58.31; H, 6.52; N, 12.95. Found: C, 57.92; H, 6.57; N, 12.86.

The product from the preceding paragraph (6.4 g, 15.2 mmol) was converted to the title compound in 52% yield (3.15 g), mp 205°-206° C., using the procedure in Example 19.

Theor. C₂₀ H₂₄ N₄ O₃ S.1/4H₂ O: C, 59.31; H, 6.10; N, 13.83. Found: C, 59.38; H, 6.00; N, 13.80.

EXAMPLE 25 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-methylthieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent and the thienopyrimidine-2,4-dione (1.82 g, 4.66 mmol) from Example 19. The title compound was isolated in 61% yield (1.13 g) after recrystallization from EtOH, mp 149°-151° C.

Theor. C₂₀ H₂₄ N₄ O₃ S: C, 59.98; H, 6.04; N, 13.90. Found: C, 59.70; H, 5.82; N, 13.95.

When in the above procedure, pentyl iodide, decyl iodide or 1-bromo-2-methylpropane are employed as the alkylating agent, the corresponding 1-pentyl, 1-decyl or 1-(2-methyl-propyl) derivative is obtained.

EXAMPLE 26 1-(Butyl)-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent, the thienopyrimidine-2,4-dione (2.0 g, 5.17 mmol) from Example 19, and butyl iodide as the alkylating agent. The title compound was isolated in 56% yield (1.28 g) after recrystallization from EtOH, mp 139°-140° C.

Theor. C₂₃ H₃₀ N₄ O₃ S: C, 62.42; H, 6.83; N, 12.66. Found: C, 62.57; H, 6.90; N, 12.68.

When in the above procedure, allyl bromide, 4-bromo-1-butene, 6-bromo-1-hexene, propargyl bromide or methyl 3-bromopropionate is employed as the alkylating agent, the corresponding 1-(propen-3-yl), 1-(buten-4-yl), 1-(hexen-6-yl), 1-(propyn-3-yl) or 1-((2-methoxycarbonyl)ethyl) derivative is obtained.

EXAMPLE 27 1-[4-(Ethoxycarbonyl)butyl]-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as solvent, the thienopyrimidine-2,4-dione (3.0 g, 7.76 mmol) from Example 19, and ethyl 5-bromovalerate was used as the alkylating agent. The title compound was isolated in 82% yield (3.3 g), after recrystallization from EtOH, mp 118°-119° C.

Theor. C₂₆ H₃₄ N₄ O₅ S: C, 60.68; H, 6.66; N, 10.87. Found: C, 60.72; H, 6.67; N, 10.83.

When the above product is treated with ammonia in accordance with Weinreb et al., vide supra, the corresponding 1-(4-butyramide) derivative is obtained.

EXAMPLE 28 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced from N-(3-carboethoxythien-2-yl)-N'-(2-chloroethyl)urea which was prepared in the same fashion as described for N-(3-carbomethoxythien-4-yl)-N'-(2-chloroethyl)urea in Example 1(a) except that the thiophene was ethyl 2-amino-3-thiophenecarboxylate (9.5 g, 55.5 mmol) and the reflux time was 16 hours. This new urea was isolated in 44% yield (6.7 g) by flash silica gel chromatography using 12.5% EtOAc in hexanes, mp 85°-87° C.

Theor. C₁₀ H₁₃ ClN₂ O₃ S: C, 43.40; H, 4.73; N, 10.12. Found: C, 43.25; H, 4.83; N, 9.97.

The product (6 g, 21.7 mmol) from the preceding paragraph was converted to N-(3-carboethoxythien-2-yl)-N'-[2-[4-(2-methoxyphenyl)piperazin-1-yl)ethyl]urea using the procedure in Example 19. This intermediate urea was isolated on 74% yield (6.99 g) with mp 129°-132° C.

Theor. C₂₁ H₂₈ N₄ O₄ S: C, 58.31; H, 6.52; N, 12.95. Found: C, 58.50; H, 6.81; N, 12.85.

The title compound was produced from the product (6.0 g, 13.9 mmol) above in 78% yield (4.18 g), mp 234°-236° C., using the procedure in Example 19.

Theor. C₁₉ H₂₂ N₄ O₃ S: C, 58.80; H, 5.80; N, 14.76. Found: C, 59.05; H, 5.74; N, 14.50.

EXAMPLE 29 3-[2-[4-(2-Methylphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using 1-(2-methylphenyl)piperazine hydrochloride and the chloroethyl urea (4.0 g, 14.4 mmol) described in Example 28. The intermediate urea, N-(3-carboethoxythien-2-yl)-N'-[2-[4-(2-methylphenyl)piperazin-1-yl]ethyl]urea, was isolated in 53% yield (3.2 g), mp 118°-123° C.

Theor. C₂₁ H₂₈ N₄ O₃ S: C, 60.55; H, 6.78; N, 13.45. Found: C, 60.37; H, 6.95; N, 13.38.

The product from the preceding paragraph (3.2 g, 7.68 mmol) was converted to the title compound in 89% yield (2.5 g) after recrystallization from EtOH, mp 191°-193° C., using the procedure in Example 19.

Theor. C₁₉ H₂₂ N₄ O₂ S: C, 61.60; H, 5.99; N, 15.12. Found: C, 61.35; H, 6.21; N, 14.98.

EXAMPLE 30 3-[2-[4-(2-Chlorophenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced according to the procedure of Example 19 using 1-(2-chlorophenyl)piperazine hydrochloride, the chloroethyl urea (4.0 g, 14.4 mmol) described in Example 28 and an initial reflux time of 4 days. The intermediate urea, N-(3-carbomethoxythien-2-yl)-N'-[2-[4-(2-chlorophenyl)piperazin-1-yl]ethyl]urea, was isolated in 81% yield (5.1 g), mp 141°-143° C.

Theor. C₂₀ H₂₅ ClN₄ O₃ S: C, 54.98; H, 5.77; N, 12.82. Found: C, 55.21; H, 6.07; N, 12.85.

The product from the preceding paragraph (5.0 g, 11.4 mmol) was converted to the title compound in 85% yield (3.77 g) after trituration with hot EtOH, mp 216°-217° C., using the procedure in Example 19.

Theor. C₁₈ H₁₉ ClN₄ O₂ S: C, 55.31; H, 4.90; N, 14.33. Found: C, 55.31; H, 4.95; N, 14.24.

EXAMPLE 31 3-[2-(4-Phenylpiperazin-1-yl)ethyl]thieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using 1-phenylpiperazine, the chloroethyl urea (2.5 g, 9.03 mmol) described in Example 28, and an initial reflux period of 4 days. The intermediate, N-(3-carboethoxythien-2-yl)-N'-[2-(4-phenylpiperazin-1-yl)ethyl]urea, was isolated in 85% yield (3.1 g), mp 117°-120° C.

Theor. C₂₀ H₂₆ N₄ O₃ S: C, 59.68; H, 6.51; N, 13.92. Found: C, 59.72; H, 6.73; N, 13.83.

The product from the preceding paragraph (3.1 g, 7.7 mmol) was converted to the title compound in 89% yield (2.43 g) after trituration with hot ethanol, mp 228°-230° C., using the procedure in Example 19.

Theor. C₁₈ H₂₀ N₄ O₂ S: C, 60.65; H, 5.66; N, 15.72. Found: C, 60.64; H, 5.81; N, 15.62.

EXAMPLE 32 3-[2-[4-(4-Methoxyphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using 1-(4-methoxyphenyl)piperazine hydrochloride, the chloroethyl urea (2.5 g, 9.03 mmol) described in Example 28, and an initial reflux period of 6 days. The intermediate, N-(3-carboethoxythien-2-yl)-N'-[2-[4-(4-methoxyphenyl)piperazin-1-yl]ethyl]urea, was isolated in 51% yield (2.0 g), mp 103°-106° C.

Theor. C₂₁ H₂₈ N₄ O₄ S: C, 58.31; H, 6.52; N, 12.95. Found: C, 58.01; H, 6.62; N, 12.89.

The product from the preceding paragraph (2.0 g, 4.62 mmol) was converted to the title compound in 97% yield (1.74 g) after trituration with hot EtOH, mp 249°-251° C., using the procedure in Example 19.

Theor. C₁₉ H₂₂ N₄ O₃ S: C, 59.05; H, 5.74; N, 14.50. Found: C, 58.81; H, 5.69; N, 14.40.

EXAMPLE 33 3-[3-[4-(2-Methoxyphenyl)piperazin-1-yl]propyl]thieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 19 using N-(3-carboethoxythien-2-yl)-N'-(3-chloropropyl) urea which was produced in the same fashion as that described in Example 24 except that the thiophene was ethyl 2-amino-3-thiophenecarboxylate (4.96 g, 29 mmol). This new urea was isolated in 51% yield (4.3 g) after flash silica gel chromatography using 15% EtOAc in hexane, mp 92°-95° C.

Theor. C₁₁ H₁₅ ClN₂ O₃ S: C, 45.44; H, 5.20; N, 9.63. Found: C, 45.84; H, 5.30; N, 9.38.

The product from the preceding paragraph (4.2 g, 14.4 mmol) was converted to the intermediate urea, N-(3-carboethoxythien-2-yl)-N'-[3-[4-(2-methoxyphenyl)piperazin-1-yl]propyl]urea, using the procedure in Example 19 in 64% yield (4.1 g), mp 43°-50° C.

Theor. C₂₂ H₃₀ N₄ O₄ S: C, 59.17; H, 6.77; N, 12.55. Found: C, 58.75; H, 7.16; N, 12.42.

The product from the preceding paragraph (4.0 g, 8.96 mmol) was converted to the title compound in 50% yield (1.8 g) after trituration with hot EtOH, mp 217°-218° C., using the procedure in Example 19.

Theor. C₂₀ H₂₄ N₄ O₃ S: C, 59.98; H, 6.04; N, 13.99. Found: C, 59.94; H, 6.13; N, 13.87.

EXAMPLE 34 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-5-methylthieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced from N-(2-chloroethyl)-N'-(3-ethoxycarbonyl-4-methylthien-2-yl)urea which was prepared in the same fashion as described for N-(3-carbomethoxythien-4-yl)-N'-(2-chloroethyl)urea in Example 1(a) except that the thiophene was ethyl 2-amino-4-methyl-3-thiophenecarboxylate (18.5 g, 0.1 mol). This chloroethyl urea was isolated in 76% yield (22.3 g) and crystallized from CH₂ Cl₂ /ether (1:1), mp 126.5°-130° C.

Theor. C₁₁ H₁₅ ClN₂ O₃ S: C, 45.43; H, 5.20; N, 9.64. Found: C, 45.61; H, 5.39; N, 9.95.

The product from the preceding paragraph (5.8 g, 20 mmol) was converted to the title compound in 72% yield (5.8 g) following the procedure in Example 1(b), and this material was converted to its hydrochloride salt with isopropanolic hydrogen chloride, mp 209°-213° C.

Theor. C₂₀ H₂₄ N₄ O₃ S.HCl.1/2H₂ O: C, 53.86; H, 5.88; N, 12.56. Found: C, 54.19; H, 5.89; N, 12.66.

When in the above procedure, methyl 2-amino-5-methyl-3-thiophenecarboxylate hydrochloride, methyl 2-amino-4,5-diethyl-3-thiophenecarboxylate hydrochloride, methyl 2-amino-5-nitro-3-thiophenecarboxylate hydrochloride or methyl 2-amino-5-propyl-3-thiophenecarboxylate hydrochloride is employed, the corresponding 7-methyl, 5,7-diethyl, 5-nitro or 5-propyl derivative is obtained.

EXAMPLE 35 6-Chloro-3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced from N-(3-carboethoxy-5-chlorothien-2-yl)-N'-(2-chloroethyl)urea which was prepared by treating a 100 ml CH₂ Cl₂ solution of the chloroethyl urea of Example 28 (5.0 g, 18.1 mmol) with 1.52 ml (19 mmol) of sulfuryl chloride at 0°-5° C. After the reaction mixture had been stirred at room temperature for 18 hours, the mixture was concentrated to 20 ml in vacuo and diluted with hexane. The intermediate urea was isolated in 84% (4.74 g) yield, mp 122°-128° C.

Theor. C₁₀ H₁₂ Cl₂ N₂ O₃ S: C, 38.60; H, 3.89; N, 9.00. Found: C, 38.66; H, 4.07; N, 8.87.

The product from the preceding paragraph (4.7 g, 15.1 mmol) was converted to the intermediate urea, N-(3-carboethoxy-5-chlorothien-2-yl)-N'-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]urea, using the procedure in Example 19 except that the reflux period was 3.5 days. This material was isolated in 86% yield (6.03 g), mp 53°-58° C.

Theor. C₂₁ H₂₇ ClN₄ O₄ S: C, 54.01; H, 5.82; N, 12.00. Found: C, 54.35; H, 6.28; N, 11.62.

The product from the preceding paragraph (6.0 g, 12.8 mmol) was converted to the title compound in 63% yield (3.42 g) after recrystallization from EtOH, mp 228°-230° C., using the procedure in Example 19.

Theor. C₁₉ H₂₁ ClN₄ O₃ S: C, 54.22; H, 5.03; N, 13.31. Found: C, 54.13; H, 5.20; N, 13.24.

EXAMPLE 36 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-5,6-dimethylthieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced from N-(3-carboethoxy-4,5-dimethylthien-2-yl)-N'-(2-chloroethyl)urea, which was prepared in the same fashion as described for N-(3-carbomethoxythien-4-yl)-N'-(2-chloroethyl)urea in Example 1(a) except that the thiophene was ethyl 2-amino-4,5-dimethyl-3-thiophenecarboxylate (7.0 g, 35.1 mmol). This chloroethyl urea was isolated in 61% yield (6.5 g) after flash silica gel chromatography using 10% EtOAc in hexanes, mp 115°-116° C.

Theor. C₁₂ H₁₇ ClN₂ O₃ S: C, 47.29; H, 5.62; N, 9.19. Found: C, 47.25; H, 5.73; N, 9.14.

The product from the preceding paragraph (6.0 g, 21.7 mmol) was converted to the intermediate urea, N-(3-carboethoxy-4,5-dimethylthien-2-yl)-N'-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]urea, in 89% yield (8.6 g), mp 56°-62° C., using the procedure in Example 19.

Theor. C₂₃ H₃₂ N₄ O₄ S: C, 59.98; H, 7.00; N, 12.16. Found: C, 59.60; H, 7.30; N, 11.80.

The product from the preceding paragraph (8.5 g, 18.5 mmol) was converted to the title compound in 85% yield (6.5 g) after trituration with hot EtOH, mp 196°-197° C., using the procedure in Example 19.

Theor. C₂₁ H₂₆ N₄ O₃ S: C, 60.85; H, 6.32; N, 13.52. Found: C, 60.70; H, 6.60; N, 13.48.

EXAMPLE 37 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-methylthieno[2,3-d]pyrimidine-2,4-dione

The title compound was produced following the procedure of Example 13 using dimethylformamide as the solvent and the thienopyrimidine-2,4-dione (2.0 g, 5.17 mmol) of Example 28. The title compound was isolated in 61% yield (1.13 g) after recrystallization from EtOH, mp 174°-176° C.

Theor. C₂₀ H₂₄ N₄ O₃ S: C, 59.98; H, 6.04; N, 13.99. Found: C, 60.04; H, 6.19; N, 14.03.

When in the above procedure, pentyl iodide, decyl iodide or 1-bromo-2-methylpropane is employed as the alkylating agent, the corresponding 1-pentyl, 1-decyl or 1-(2-methyl-propyl) derivative is obtained.

When in the above procedure, allyl bromide, 4-bromo-1-butene, 6-bromo-1-hexene, propargyl bromide or methyl 3-bromopropionate is employed as the alkylating agent, the corresponding 1-(propen-3-yl), 1-(buten-4-yl), 1-(hexen-6-yl), 1-(propyn-3-yl) or 1-((2-methoxycarbonyl)ethyl) derivative is obtained.

EXAMPLE 38 1-Acetyl-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

A solution of 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione (1.0 g, 2.6 mmol) in methylene chloride (50 ml) was cooled by an external ice bath and triethylamine (0.393 g, 3.88 mmol) and acetyl chloride (0.305 g, 3.88 mmol) were added. After stirring for 1 hour, the mixture was warmed to room temperature and quenched with water (10 ml). The separated organic layer was washed with water and saturated brine and dried over magnesium sulfate. The solution was concentrated in vacuo, treated with toluene (10 ml) and reconcentrated to give the product (0.93 g, 83.5% yield) which was recrystallized from methylene chloride-hexanes to give the analytical sample as light brown crystals, mp 128°-129° C.

Theor. C₂₁ H₂₄ N₄ O₄ S: C, 58.86; H, 5.65; N, 13.08. Found: C, 58.78; H, 5.69; N, 13.05.

EXAMPLE 39 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-(2-methyl-1-oxopropyl)thieno[3,4-d]pyrimidine-2,4-dione

When isobutyryl chloride (0.662 g, 6.2 mmol) was used as the acylating agent in the procedure of Example 38, the title compound was isolated as a white crystalline solid (1.4 g, 58.9% yield), mp 129°-130.5° C.

Theor. C₂₃ H₂₈ N₄ O₄ S: C, 60.50; H, 6.18; N, 12.27. Found: C, 60.58; H, 6.28; N, 11.88.

EXAMPLE 40 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-(1-oxohexyl)thieno[3,4-d]pyrimidine-2,4-dione

When hexanoyl chloride (0.836 g, 6.2 mmol) was used as the acylating agent in the procedure of Example 38, the title compound was obtained as a buff colored solid (1.24 g, 49.2% yield), mp 81°-82.5° C.

Theor. C₂₅ H₃₂ N₄ O₄ S: C, 61.98; H, 6.66; N, 11.56. Found: C, 61.95; H, 6.84; N, 11.14.

EXAMPLE 41 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-(2,2-dimethyl-1-oxopropyl)thieno[3,4-d]pyrimidine-2,4-dione

When trimethylacetyl chloride (0.749 g, 6.2 mmol) was used as the acylating agent in the procedure of Example 38, the title compound was obtained as a buff colored solid (1.57 g, 64.1% yield), mp 116°-117° C.

Theor. C₂₄ H₃₀ N₄ O₄ S: C, 61.25; H, 6.49; N, 11.91. Found: C, 61.32; H, 6.49; N, 11.59.

EXAMPLE 42 1-Benzoyl-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

When benzoyl chloride (0.873 g, 6.2 mmol) was used as the acylating agent in the procedure of Example 38, the title compound was obtained as a white solid (1.2 g, 47% yield), mp 112°-113.5° C.

Theor. C₂₆ H₂₆ N₄ O₄ S: C, 63.85; H, 5.34; N, 11.42. Found: C, 63.42; H, 5.47; N, 11.23.

EXAMPLE 43 1-(4-Chlorobenzoyl)-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione

When 4-chlorobenzoyl chloride (1.08 g, 6.2 mmol) was used as the acylating agent in the procedure of Example 38, the title compound was obtained as a white solid (0.822 g, 30.1% yield), mp 173°-174.5° C.

Theor. C₂₆ H₂₅ ClN₄ O₄ S: C, 59.48; H, 4.80; N, 10.67. Found: C, 59.13; H, 4.69; N, 10.50.

When in the above procedure, 4-methoxybenzoyl chloride is employed, the corresponding 1-(4-methoxybenzoyl) derivative is obtained.

EXAMPLE 44 Methyl 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-2,4-dioxothieno[3,4-d]pyrimidine-1-(5-oxopentanoate)

When methyl 4-(chloroformyl)butyrate (1.02 g, 6.2 mmol) was used as the acylating agent in the procedure of Example 38, the title compound was isolated as a white crystalline solid (0.435 g, 16.3% yield), mp 94°-95° C.

Theor. C₂₅ H₃₀ N₄ O₆ S: C, 58.35; H, 5.88; N, 10.89. Found: C, 58.18; H, 5.92; N, 10.67.

EXAMPLE 45 1-Acetyl-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione

A solution of 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione (2.6 g, 6.73 mmol) in acetic anhydride (30 ml) was heated to reflux for 5 hours. Acetic anhydride was removed in vacuo. The residue was dissolved in toluene, and the toluene was removed in vacuo. This process was repeated twice to remove any residual acetic anhydride. The residue was purified by flash chromatography on silica gel 60 (60 g) using 2.5% methanol in methylene chloride as eluant to give the product (1.65 g, 57% yield) as an off-white solid, mp 156°-158° C.

Theor. C₂₁ H₂₄ N₄ O₄ S: C, 58.86; H, 5.64; N, 13.07; S, 7.48. Found: C, 58.87; H, 5.75; N, 12.83; S, 7.44.

EXAMPLE 46 3-[2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl]-1-(2,2-dimethyl-1-oxopropyl)thieno[3,2-d]pyrimidine-2,4-dione

A mixture of 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione (3.23 g, 8.36 mmol) and sodium hydride (60% in mineral oil, prewashed with pentane, 435 mg, 10.9 mmol) in N,N-dimethylformamide (50 ml) was allowed to equilibrate for one hour. Trimethylacetyl chloride (1.35 ml, 10.9 mmol) was added to the resultant solution, and stirred at room temperature for 16 hours. The solution was poured into ice water (200 ml) and extracted with methylene chloride (100 ml). The methylene chloride solution was washed with water (4×100 ml) and dried over magnesium sulfate. The solvent was removed in vacuo and the resultant oil was purified by flash chromatography on silica gel 60 (100 g) using 2% methanol in methylene chloride as eluant to give the product (1.56 g, 40% yield) as a beige solid, mp 117°-120° C.

Theor. C₂₄ H₃₀ N₄ O₄ S: C, 61.26; H, 6.43; N, 11.91; S, 6.91. Found: C, 61.09; H, 6.49; N, 11.90; S, 6.76.

When in the above procedure, benzoyl chloride, 4-methoxybenzoyl chloride or 4-chlorobenzoyl chloride is employed as the acylating agent, the corresponding 2-benzoyl, 1-(4-methoxybenzoyl) or 1-(4-chlorobenzoyl) derivative is obtained.

When in the above procedures, 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione is utilized, the corresponding thieno[2,3-d]pyrimidine-2,4-dione derivative is obtained.

EXAMPLE 47 Ethyl 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-2,4-dioxothieno[3,2-d]pyrimidine-1-carboxylate

A mixture of 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione (2.62 g, 6.77 mmol) and sodium hydride (60% in mineral oil, prewashed with pentane, 325 mg, 8.13 mmol) in N,N-dimethylformamide (50 ml) was allowed to equilibrate for one hour. Ethyl chloroformate (0.78 ml, 8.13 mmol) was added to the resultant solution, and stirred at room temperature for 16 hours. The solution was poured into ice water (200 ml) and the resultant solid was collected by filtration, washed with water and air dried. The solid was purified by flash chromatography on silica gel 60 (100 g) using 1% methanol in methylene chloride as eluant to give the product (0.88 g, 28% yield) as a colorless solid, mp 121°-122° C.

Theor. C₂₂ H₂₆ N₄ O₅ S: C, 57.62; H, 5.71; N, 12.21; S, 6.99. Found: C, 53.87; H, 5.78; N, 11.93; S, 6.93.

EXAMPLE 48 Antihypertensive Activity

The antihypertensive activity of the compounds was tested as follows. Adult male spontaneously hypertensive rats (SHR) were placed in restrainers in a chamber warmed to 32° C. A standard indirect method employing a pneumatic pulse transducer and inflatable tail cuff was used to measure systolic blood pressure (SBP) in the conscious state. After baseline SBPs were recorded, groups of 4-6 SHR received a single oral dose of drug or vehicle (0.5% methylcellulose) administered with a gavage tube at doses of 0.5-20 mg/kg. SBPs were obtained at 1/2, 1, 2, 3 and 4 hours post-treatment. Changes in SBPs were statistically compared to the vehicle effect using Students t test at p=0.05. The results for representative compounds are shown in Table I.

                  TABLE I                                                          ______________________________________                                         Antihypertensive Effect of Representative                                      Thienopyrimidine-2,4-dione Derivatives                                                                 Change from Pre-Drug                                   Compound                Systolic Blood                                         (Example)  Dose (mg/kg) Pressure (mm Hg)                                       ______________________________________                                          1         0.5          -83                                                               1.25         -63                                                               2.50         -106                                                    2         10           -70                                                     3         1.25         -36                                                     4         1.25         -51                                                     5         10           -20                                                               20           -19                                                     6         10           -51                                                     7         20           -52                                                     8         10           -56                                                     9         10           -68                                                    10         10           -76                                                    11         10           -38                                                    12         1.25         -66                                                               10           -83                                                    13         1.25         -67                                                    14         10           -50                                                    15         10           -52                                                    16         10           -54                                                    17         10           -55                                                    18         1.25         -37                                                               10           -87                                                    19         1.25         -74                                                               2.50         -50                                                      .sup. 19 (urea                                                                          10           -35                                                    intermediate)                                                                  20         1.25         -33                                                    21         1.25         -30                                                    22         10           -68                                                    23         10           -48                                                    24         10           -43                                                    25         1.25         -56                                                    26         1.25         -28                                                               10           -78                                                    27         2.5          -30                                                    28         1.25         -50                                                               2.50         -68                                                    29         1.25         -19                                                               10           -70                                                    30         10           -43                                                    31         10           -45                                                    32         10           -40                                                    33         10           -68                                                    34         10           -56                                                    35         1.25         -25                                                               20           -91                                                    36         1.25         -23                                                               20           -50                                                    37         1.25         -28                                                    38         2.5          -44                                                    39         5            -53                                                    40         5            -42                                                    41         5            -69                                                    42         5            -64                                                    44         5            -46                                                    45         5            -58                                                    ______________________________________                                    

EXAMPLE 49 Vasodilatory Activity

The vasodilatory activity of the compounds was tested as follows. Adult mongrel dogs were anesthetized and surgically prepared for electromagnetic measurement of renal artery blood flow. A carotid artery was cannulated for measuring arterial blood pressure and drugs were administered intravenously or intraarterially (renal artery). Heart rate was monitored by a cardiotachometer. Renal vascular resistance (RVR) was calculated as the ratio of mean arterial blood pressure/renal artery blood flow. Dopamine was infused intravenously at 3 μg/kg/min for 10 minutes (1 ml/min) to determine responsiveness of each dog to renal dopamine receptor stimulation. Cumulative dose-response data were obtained by infusing the test drug at progressively increasing (usually three-fold) infusion rates, each dose being infused for five minutes. The maximum percent increase from pre-drug control in renal artery blood flow (RBF) or decrease in renal vascular resistance (RVR) was quantitated for each infusion dose. The results for representative compounds are shown in Table II.

                  TABLE II                                                         ______________________________________                                         Vasodilatory Effects of Representative Thieno-                                 pyrimidine-2,4-dione Derivatives in Anesthetized Dog                                                    Percent Change From                                   Compound   Total Cumulative                                                                             Pre-Drug Baseline                                     (Example)  Dose (mg/kg i.v.)                                                                            RBF       RVR                                         ______________________________________                                          1         1.2           +52       -46                                          2         0.2           +19       -42                                          3         6.2           +46       -42                                          4         1.2           +10       -18                                         19          0.24         +24       -40                                           .sup. 19 (urea                                                                          1.2           +17       -54                                         intermediate)                                                                  23         1.2           +15       -36                                         26         1.2           +20       -33                                         28         1.2           +15       -21                                         41         6.2           +15       -30                                         ______________________________________                                     

What is claimed is:
 1. A compound of the formula ##STR20## where ##STR21## R₁ and R₂ are the same or different and are hydrogen, F, Cl, Br, nitro, C₁ -C₃ alkyl or R₁ and R₂ together are --(CH₂)₄ -- when ##STR22## R₃ is hydrogen, C₁ -C₁₀ straight or branched-chain alkyl, C₃ -C₆ alkenyl, C₃ -C₆ alkynyl, --(CH₂)_(m) --CO₂ R₅, --(CH₂)_(m) CONR₆ R₇, --COR₈ or --CO₂ R₉ ;R₅ is hydrogen, C₁ -C₃ alkyl, pharmaceutically acceptable alkali metal ion, pharmaceutically acceptable alkaline earth metal ion or pharmaceutically acceptable quaternary ammonium ion; R₆ and R₇ are the same or different and are hydrogen or C₁ -C₃ alkyl; R₈ is C₁ -C₅ straight or branched-chain alkyl, --(CH₂)_(m) --CO₂ R₅, phenyl or phenyl substituted by F, Cl, Br, C₁ -C₂ alkyl or C₁ -C₂ alkoxy; R₉ is C₁ -C₃ alkyl; Ar is ##STR23## R₁₀ and R₁₁ are the same or different and are hydrogen, NO₂, CF₃, F, Cl, Br, C₁ -C₃ alkyl or C₁ -C₂ alkoxy; m is 2-6; and n is 2-4.
 2. A compound of claim 1 wherein R₃ is --COR₈.
 3. A compound of claim 1 wherein R₃ is --CO₂ R₉.
 4. A compound of claim 1 wherein R₃ is --(CH₂)_(m) --CO₂ R₅ or --(CH₂)_(m) --CONR₆ R₇.
 5. A compound of claim 1 wherein R₃ is hydrogen, C₁ -C₁₀ straight or branched-chain alkyl, C₃ -C₆ alkenyl or C₃ -C₆ alkynyl.
 6. A compound of claim 1 selected from the group consisting of 3-[2-[4-(2-methoxyphenyl]piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methylphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-chlorophenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(3-chlorophenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(4-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(3-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(4-chlorophenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(4-fluorophenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-(4-phenylpiperazin-1-yl)ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[3-[4-(2-methoxyphenyl)piperazin-1-yl]propyl]thieno[3,4-d]pyrimidine-2,4-dione; and 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-5-methylthieno[3,4-d]pyrimidine-2,4-dione.
 7. A compound of claim 1 selected from the group consisting of 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methylphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione; 3-[2-[4-(2-chlorophenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione; 3-[2-[4-(4-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione; 3-[2-(4-phenylpiperazin-1-yl)ethyl]thieno[3,2-d]pyrimidine-2,4-dione; and 3-[3-[4-(2-methoxyphenyl)piperazin-1-yl]propyl]thieno[3,2-d]pyrimidine-2,4-dione.
 8. A compound of claim 1 selected from the group consisting of 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methylphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione; 3-[2-[4-(2-chlorophenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione; 3-[2-(4-phenylpiperazin-1-yl)ethyl]thieno[2,3-d]pyrimidine-2,4-dione; 3-[2-[4-(4-methoxyphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione; 3-[3-[4-(2-methoxyphenyl)piperazin-1-yl]propyl]thieno[2,3-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-5-methylthieno[2,3-d]pyrimidine-2,4-dione; 6-chloro-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[2,3-d]pyrimidine-2,4-dione; and 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-5,6-dimethylthieno[ 2,3-d]pyrimidine-2,4-dione.
 9. A compound of claim 1 selected from the group consisting of 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-methylthieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-(propen-3-yl)thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-(propyn-3-yl)thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-(octyl)thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-methylthieno[3,2-d]pyrimidine-2,4-dione; 1-(butyl)-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione; and 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-methylthieno[2,3-d]pyrimidine-2,4-dione.
 10. A compound of claim 1 selected from the group consisting of 1-(2-methoxycarbonyl)ethyl-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 1-[3-(ethoxycarbonyl)propyl]-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; and 1-[4-(ethoxycarbonyl)butyl]-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione.
 11. A compound of claim 1 which is ethyl 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-2,4-dioxothieno[3,2-d]pyrimidine-1-carboxylate.
 12. A compound of claim 1 selected from the group consisting of 1-acetyl-3-[2-[4-(2 -methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-(2-methyl-1-oxopropyl)thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-(1-oxohexyl)thieno[3,4-d]pyrimidine-2,4-dione; 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-(2,2-dimethyl-1-oxopropyl)thieno[3,4-d]pyrimidine-2,4-dione; 1-benzoyl-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; 1-(4-chlorobenzoyl)-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,4-d]pyrimidine-2,4-dione; methyl 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-2,4-dioxothieno[3,4-d]pyrimidine-1-(5-oxopentanoate); 1-acetyl-3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]thieno[3,2-d]pyrimidine-2,4-dione; and 3-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-1-(2,2-dimethyl-1-oxopropyl)thieno[3,2-d]pyrimidine-2,4-dione. 